Different service users will have different requirements. Short term contracts exist for as little as 5 or 6 sessions if appropriate, or therapy can be open-ended, lasting for months and even years. When you move to a permanent therapist, they should be able to discuss your therapy in detail and help you to ascertain what type of therapy is right for you.
There are a lot of people on this board in long-term therapy (myself included) but that's not necessarily representative of the general population, and there are many different uses for therapy across the board.